Severe Weather Outbreak for the Northeast and Midwest

Originally posted on ZoomRadar

A severe weather outbreak will begin today and continue through tomorrow night across many parts of the Midwest and the Northeast. While some of the details as far as exact locations and timing go are still somewhat unknown, it is clear that by Friday morning, many will likely be cleaning up from storm damage over the past two days. This is because of unstable air which will be in place behind a warm front but in front of a cold front which will push through these portions of the country over the next two days.

First let’s concentrate on what is going on right now and into tonight. Below is the current Day 1 Outlook from the SPC showing a large area highlighted under a slight risk of severe thunderstorms across the upper Midwest and into parts of western New York. The main threat will be damaging winds from these storms but some large hail and a couple of isolated tornadoes cannot be ruled out.

Here is the Day 1 SPC Outlook showing the wind damage probabilities for this evening and tonight. A 30% chance of severe wind within 25 miles of a point is expected to occur from areas in southeastern Wisconsin east toward central Michigan. In fact, most of this area is also under a 10% or greater probability of seeing significant wind gusts in excess of 65 knots.

The threat for damaging winds will mainly occur due to straight-line winds associated with lines of thunderstorms. This is the scenario that the current 18Z NAM model run depicts as well. This line or lines of storms should fire up this evening and continue into the overnight hours. Below is the 18Z NAM run showing what the reflectivity may look like this evening around sunset.

A line of storms may be most intense right across and around that 30% area the SPC highlighted for wind damage this evening and tonight. Taking a look at the modeled CAPE and EHI values, we also see that the storms will have plenty of instability to work with.

Storms are expected to continue through the overnight hours and into tomorrow morning, weakening some in the early morning hours. However, a line or lines of storms will refire up tomorrow most likely around midday and continue to track off to the east. Here is a look at what the 18Z NAM model is thinking right now as far as what the reflectivity may look like. The top image shows the reflectivity around midday into the early afternoon whereas the bottom image shows how it may appear in the late afternoon.

Once again, these storms will have plenty of instability with CAPE values approaching and exceeding 3000 J/kg according to the 18Z NAM model.

EHI values will also be good in some areas meaning that if any supercells can form out in front of the main line of storms, there could be a chance for a couple tornadoes.

For these reasons as well as the great upper air support that these storms will be dealing with, the SPC has issued a moderate risk for some areas in their Day 2 Outlook. These areas are the areas highlighted in purple, indicating a 45% chance of severe weather within 25 miles of a point, as well as a 10% or greater probability of significant severe weather within 25 miles of a point.

A large area is looking at a slight chance of severe weather tomorrow but the areas at the greatest risk will be from southern Illinois into Indiana, Ohio, Pennsylvania, New Jersey, New York, southern Vermont and New Hampshire, Massachusetts, Rhode Island, and Connecticut. Residents of these areas should prepare for the potential of straight-line wind damage, as this will be the main threat tomorrow and tomorrow night. If the line of storms becomes strong enough, and this is the current thinking, we could be looking at a long lived derecho which could produce damage similar to the one that affected areas of the Midwest and Mid-Atlantic on June 29th of this year.

The threat could be very extreme in some areas tomorrow so stay alert to the latest weather conditions and remember to seek shelter in advance of these storms.

Historic Heat and Drought

Originally posted on ZoomRadar

If you could ask people throughout the contiguous United States what two words they would use to describe the weather conditions this spring and so far this summer, I would imagine the answers would run along the lines of hot and dry. This has been the case for most areas in the lower 48 states so far this year, though it is important to note that this is not true for everywhere in the lower 48. In fact, some areas have seen above normal precipitation so far this year, including areas of central Texas, most of Maine, as well as many areas of the Pacific Northwest, northern Rockies, and northern Plains.

The graphic below shows how temperatures compared to the 1981 to 2010 average across the lower 48 last month. Despite the month officially rating as the fourth warmest June on record globally, with records dating back to 1880, some areas of the U.S. saw below normal temperatures during this time period, denoted in blues below.



But like I stated previously, most of the nation has been experiencing heat and little rainfall. June marked the 328th continuous month with temperatures above the 20th century average according to NOAA. The United States seems to be taking the brunt of the heat as well. Temperatures globally in June were nearly two degrees Fahrenheit above average on the world’s landmasses and have been 1.57 degrees above average so far this year. But in the U.S., temperatures have been averaging 4.5 degrees above normal so far this year, now that is some heat!

And as if the heat was not enough to worry about, drought conditions have continued to worsen across a vast portion of the lower 48 states. Drought conditions are depicted in the map below as of July 10th and have likely continued to worse across many portions.

In terms of the area affected by this drought, this is now officially the worse drought since the 1950s. About 61% of the continental U.S. currently qualifies as being in some level of a drought according to the U.S. Drought Monitor. The Palmer Drought Index, an older and less detailed index, reports that 56% of the United States is currently under drought conditions. The last time drought covered more area in the lower 48 states was in December 1956.

This current drought does not compare to past droughts in duration yet, but with no major relief in the near future, conditions may continue for some time. Below is the NAM model depicting how much precipitation may fall over the next 84 hours. While some relief may fall over this time period, it will not affect all areas and will not be enough to eliminate the precipitation deficit, though any help will be very welcomed in these areas.

Below is the precipitation across the United States over the past 60 days when compared to normal, showing many areas suffering from precipitation deficits.

All of this heat and lack of precipitation has unfortunately led to many issues across the nation and will continue to do so. Heat related deaths have occurred in many states and many more have likely suffered from heat related illnesses. Additionally, dry conditions have wreaked havoc on the nation’s corn crop, with the U.S. Department of Agriculture now reporting that 38% of the crop is in poor or very poor condition. Problems have also arisen in the form of wildfires due to the dry conditions. Below is a map showing the current large wildfires across the United States.

The summer will likely continue with more hot and dry conditions so it is important to take precautions to protect your life and property. Be sure to stay hydrated, take breaks from the sun, monitor any fires you start closely, and of course stay up to date on the latest weather information.